학술논문
SILVERRUSH. VIII. Spectroscopic Identifications of Early Large-scale Structures with Protoclusters over 200 Mpc at z ∼ 6–7: Strong Associations of Dusty Star-forming Galaxies
Document Type
article
Author
Harikane, Yuichi; Ouchi, Masami; Ono, Yoshiaki; Fujimoto, Seiji; Donevski, Darko; Shibuya, Takatoshi; Faisst, Andreas L; Goto, Tomotsugu; Hatsukade, Bunyo; Kashikawa, Nobunari; Kohno, Kotaro; Hashimoto, Takuya; Higuchi, Ryo; Inoue, Akio K; Lin, Yen-Ting; Martin, Crystal L; Overzier, Roderik; Smail, Ian; Toshikawa, Jun; Umehata, Hideki; Ao, Yiping; Chapman, Scott; Clements, David L; Im, Myungshin; Jing, Yipeng; Kawaguchi, Toshihiro; Lee, Chien-Hsiu; Lee, Minju M; Lin, Lihwai; Matsuoka, Yoshiki; Marinello, Murilo; Nagao, Tohru; Onodera, Masato; Toft, Sune; Wang, Wei-Hao
Source
The Astrophysical Journal. 883(2)
Subject
Language
Abstract
We have obtained three-dimensional maps of the universe in ∼200 × 200 × 80 comoving Mpc3 (cMpc3) volumes each at z = 5.7 and 6.6 based on a spectroscopic sample of 179 galaxies that achieves ⪆80% completeness down to the Lyα luminosity of, based on our Keck and Gemini observations and the literature. The maps reveal filamentary large-scale structures and two remarkable overdensities made out of at least 44 and 12 galaxies at z = 5.692 (z57OD) and z = 6.585 (z66OD), respectively, making z66OD the most distant overdensity spectroscopically confirmed to date, with >10 spectroscopically confirmed galaxies. We compare spatial distributions of submillimeter galaxies at z ≃ 4-6 with our z = 5.7 galaxies forming the large-scale structures, and detect a 99.97% signal of cross-correlation, indicative of a clear coincidence of dusty star-forming galaxy and dust-unobscured galaxy formation at this early epoch. The galaxies in z57OD and z66OD are actively forming stars with star-formation rates (SFRs) ⪆5 times higher than the main sequence, and particularly the SFR density in z57OD is 10 times higher than the cosmic average at the redshift (a.k.a. the Madau-Lilly plot). Comparisons with numerical simulations suggest that z57OD and z66OD are protoclusters that are progenitors of the present-day clusters with halo masses of ∼1014 M o˙